MacBook - Replaced screen now keyboard doesnt fit?

Hello we recently tried to replace my macbook screen because we read that it was fairly simple and it would cost us about $200 less.

We got the screen in place and we got everything back in, but when we put the keyboard on it didn't fit properly.

The keyboard doesn't sit flush on the back spine of the computer.
Has anyone had this problem?
What might be the cause of this problem?

Thank you